2 cups and toilet paper roll - it's gonna get loud in here!
Cell phone speakers are tiny and tinny but you can make your music sound Bigger and better with this project.
The sounds from your cell phone are waves spreading out in all directions. When you put your phone inside this speaker the waves bounce around inside the tube and cups so almost all of the sound waves come out the front. Try crumpling a half of a paper towel and placing loosely inside the end of each tube. This will absorb of the high pitched sounds and make your music sound less tinny.